/*
 * EventAttribute.java January 2010
 *
 * Copyright (C) 2010, Niall Gallagher <niallg@users.sf.net>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

package wx.xml.simpleframework.xml.stream;

/**
 * The <code>EventAttribute</code> object represents an attribute
 * that is associated with an event node. An attribute is required
 * to provide the name and value for the attribute, and optionally
 * the namespace reference and prefix. For debugging purposes the
 * source object from the internal XML provider can be acquired.
 *
 * @author Niall Gallagher
 */
abstract class EventAttribute implements Attribute {

    /**
     * This is used to acquire the namespace prefix associated with
     * this attribute. A prefix is used to qualify the attribute
     * within a namespace. So, if this has a prefix then it should
     * have a reference associated with it.
     *
     * @return this returns the namespace prefix for the attribute
     */
    public String getPrefix() {
        return null;
    }

    /**
     * This is used to acquire the namespace reference that this
     * attribute is in. A namespace is normally associated with an
     * attribute if that attribute is prefixed with a known token.
     * If there is no prefix then this will return null.
     *
     * @return this provides the associated namespace reference
     */
    public String getReference() {
        return null;
    }

    /**
     * This is used to return the source of the attribute. Depending
     * on which provider was selected to parse the XML document an
     * object for the internal parsers representation of this will
     * be returned. This is useful for debugging purposes.
     *
     * @return this will return the source object for this event
     */
    public Object getSource() {
        return null;
    }

    /**
     * This returns true if the attribute is reserved. An attribute
     * is considered reserved if it begins with "xml" according to
     * the namespaces in XML 1.0 specification. Such attributes are
     * used for namespaces and other such details.
     *
     * @return this returns true if the attribute is reserved
     */
    public boolean isReserved() {
        return false;
    }
}
